New Design System + Codebase Refresh (#1823)

Since the very first 0.1.0-alpha.1 release, we've been moving quickly to add new features to the Maybe app. In doing so, some parts of the codebase have become outdated, unnecessary, or overly-complex as a natural result of this feature prioritization.

Now that "core" Maybe is complete, we're moving into a second phase of development where we'll be working hard to improve the accuracy of existing features and build additional features on top of "core". This PR is a quick overhaul of the existing codebase aimed to:

- Establish the brand new and simplified dashboard view (pictured above)
- Establish and move towards the conventions introduced in Cursor rules and project design overview #1788
- Consolidate layouts and improve the performance of layout queries
- Organize the core models of the Maybe domain (i.e. Account::Entry, Account::Transaction, etc.) and break out specific traits of each model into dedicated concerns for better readability
- Remove stale / dead code from codebase
- Remove overly complex code paths in favor of simpler ones

lib/tasks/demo_data.rake

@@ -5,8 +5,13 @@ namespace :demo_data do
     Demo::Generator.new.reset_and_clear_data!(families)
   end
 
-  task reset: :environment do
-    families = [ "Demo Family 1", "Demo Family 2", "Demo Family 3", "Demo Family 4", "Demo Family 5" ]
+  task :reset, [ :count ] => :environment do |t, args|
+    count = (args[:count] || 1).to_i
+    families = count.times.map { |i| "Demo Family #{i + 1}" }
     Demo::Generator.new.reset_data!(families)
   end
+
+  task multi_currency: :environment do
+    Demo::Generator.new.generate_multi_currency_data!
+  end
 end